Final answer:
Birds migrate due to changes in resource availability, seeking food, mates, and suitable breeding grounds. They navigate using environmental cues and follow established migratory routes, despite the high energy costs and risks involved.
Step-by-step explanation:
Understanding Bird Migration
Birds migrate on a seasonal schedule primarily as an evolved response to changes in resource availability. This includes seeking out warmer climates with sufficient food, finding mates for reproduction, or reaching suitable breeding grounds. Factors such as temperature, day length, and food scarcity trigger migration. Birds and other animals have adapted to migrate, following routes known as flyways. These migratory paths are often the same year after year and can involve remarkable distances. Birds may use environmental cues such as the sun position, wind patterns, and landmarks like rivers and coastlines to navigate their routes.
Adaptations like migration are crucial for survival in animals that live in environments with seasonal changes. For example, the Arctic Tern makes an impressive 40,000 km (24,000 mi) journey between its feeding and breeding grounds annually. Similarly, monarch butterflies and other animals exhibit migratory behaviors to cope with changing temperatures and food availability. Even though migration is energetically costly and carries risks, it is essential for the survival of many species.